Chip cards have long been known and are being increasingly used for example as phone cards, identification cards or the like. There are standards which define the dimensions and technical details of such chip cards. ISO 7810 and ISO 7816 are examples of these standards.
At present, chip cards are divided into three categories, contactless chip cards, chip cards with contacts and so-called combi cards. Both the chip cards with contacts and the combi cards have a contact zone, which zones provide contacts in accordance with the aforementioned standards. These contacts are connected to a circuit integrated in the chip card. The arrangement of these contact areas on the chip card is clearly defined by the standards mentioned. The contact zones of the card contacts currently comprise a suitable metallic surface, produced for example from Au, NiPdAg or similar materials. The individual contact areas are separated in an isolating manner from one another by separating channels.
As chip cards become increasingly significant, there is likewise increasing interest in carrying out manipulations on them.
WO 97/33252, for example, discloses a method for verifying the authenticity of documents in the form of chip cards. This is achieved by scanning documents comprising a base material of the chip card with embedded foreign bodies, the physical properties of which differ from those of the base material and are distributed randomly within it, by a detector when they are first issued in at least one scanning track selected by a random generator to detect foreign bodies. After that, the output values of the detector are recorded in a register which is provided in the chip of the chip card and is blocked after an initialization, the stored contents of which register can neither be read nor manipulated from the outside. When the document prepared in this way is used, its foreign body information is constantly read by a detector and buffer-stored in a further register in the chip and compared internally with data on the pattern of the foreign bodies stored in the first register. If the comparison produces a match, the document is released. The disadvantage of this procedure is that the identification, which is based on the assignment of the chip to the card, takes place at a relatively late point in time.